#[non_exhaustive] didn't get stabilized for downstream use until several years after Rust 1.0, which probably is why it isn't super commonly seen in the wild st

#[non_exhaustive] didn't get stabilized for downstream use until several years after Rust 1.0, which probably is why it isn't super commonly seen in the wild still, but I think the standard library has been using it since 1.0 for things like `std::io::ErrorKind`.